Customized Fusing and Milling

Refractories manufacturers seeking custom-fused minerals often approach an expert who has the skills and instruments for the evaluation of new fused mineral concepts and products. Most of the manufacturers don’t have the expertise or the furnaces to conduct their experiments of their own and don’t want to spend money on capital equipment for performing a few product trails with dubious results.


Although the research and development experts at these firms have a general idea about the product they would like to produce, they usually don’t have the experience in electric-arc fusion to evaluate their concept.

Scaled-down large electric-arc furnace technology can address the necessity for small-scale furnace runs. Moreover, small-scale pilot fusion and milling plants are capable of serving the requirements of manufacturers seeking small amounts (5-100 lbs) of special fused minerals. Washington Mills, a manufacturer and supplier of fused mineral products and abrasive materials, offers sample size custom fusions as well as new product testing and development services to customers.

Advantages of Trial-Size Furnace and Small-Scale Pilot Fusion and Milling Plants

A trial-size furnace reduces material wastage as it produces samples of a few pounds. Based on the result, it is possible to alter the composition of raw materials by varying the quantity of the ingredients until the sample matches the desired product concept.

If it is successful, then scaling up the process to make products, ranging from as little as 10-100 lbs to as high as 300+ tons, based on the customer requirement for testing.

Custom small-scale milling, crushing, and magnetic separation can process small quantities of various kinds of fused products. In certain instances, it is possible to apply special surface treatments to the final product to improve specific product properties.

It may be necessary to reduce the new fused material obtained from the furnace to different sizes depending on the specific application for the newly developed product. Some processes may need the fused mineral in coarse particle sizes while others require in a fine powder form.

Milling equipment has been designed to reduce the furnaced product to a specific size based on a variety of final applications. It is possible to perform custom fusions with virtually any combination of oxide materials and with some carbides.

Custom-fused products have been manufactured for a myriad of applications such as abrasives, technical ceramics, space research, aerospace, thermal sprays, and refractories. Examples of fused materials are shown in the following table:

Table. Examples of Fused Materials

  • Alumina (Fused Alumina)
  • Alumina-Zirconia (80-20% / 60-40%)
  • Alumina-Zirconia-Magnesia (57-10-32%)
  • Alumina-Zirconia-Titania (72-26-2%)
  • Alumina-Chrome Oxide (Cr2O3 varied by 0.3-99%)
  • Alumina-Nickel Oxide (56-44%)
  • Alumina-Titania-Yttria (94-3-3%)
  • Aluminum-Titania (98-2% / 87-13% / 60-40%)
  • Alumina-Silica-Zirconia-Titania (70-20-5-2%)
  • Alumina-Magnesia-Silica (14-35-51%, Cordierite)
  • Calcia Stabilized Zirconia (4% Lime)
  • Calcia-Silica (64-34%, Larnite)
  • Calia-Yttria-Manganese Oxide (26-25-49%)
  • Calcium Oxide (Fused Lime)
  • Cerium Oxide (Fused Ceria)
  • Erbium Oxide (Fused Erbia)
  • FerroSilicon FeSi (84-15%)
  • Lanthanum Oxide (Fused Lanthanum Oxide)
  • Lime-Magnesia-Alumina-Silica (37-7-12-48%)
  • Magnesia-Chrome Oxide (20-80%)
  • Magnesia-Chrome Oxide (40-60%)
  • Magnesia-Alumina (87-13%)
  • Magnesia-Alumina-Zirconia (82-13-5%)
  • Magnesia-Chrome-Alumina-Iron Oxide (64-19-6-11%)
  • Magnesia-Chrome-Alumina-Iron Oxide (53-37-4-6%)
  • Magnesia-Silica (55-45%, Forsterite)
  • Praseodymium Oxide (Fused Praseodymium Oxide)
  • TiO2 (Fused Titania)
  • Yttria (Fused Yttria)
  • Zirconium-Dysprosium Oxide
  • Zirconium-Dyprosium-Indium Oxide
  • Zirconium Diboride (ZrB2)
  • Zirconia-Ytterbium Oxide
  • Zirconia-Yttria (91-9% / 93-7%)

Custom fusion runs allow composition change as required and the necessary adjustments all through the fusion process.

Scaling Up

In certain instances, the concept product does not meet the expectations. In others, the product fulfills or surpasses research expectations and therefore the manufacturer can seek ways for scaling up the production. The experience gained in operating electric-arc furnaces and the knowledge gained about the minerals involved are helpful to achieve good results during the scale-up process.

Laboratory Testing

An on-site, fully equipped analytical laboratory plays a key role in the custom fusion process. After the production of the concept product, it can be fully tested in the laboratory for its chemical and physical characteristics. The laboratory must have X-ray fluorescence and X-ray diffraction instruments to carry out chemical or elemental analysis in addition to crystal structure analysis and phase analysis.

Analyzing grains for size and particle shape

Analyzing grains for size and particle shape

Bulk density testing, particle size analysis, friability, magnetics, and specific gravity are other key laboratory tests. On-site laboratory testing delivers immediate results, thus extending the flexibility of the fusion process as it allows the on-the-fly adjustment of ingredients and furnace parameters to prevent costly errors.

X-ray fluorescence analysis

X-ray fluorescence analysis


The combination of a research and development group and a custom fusion team provides the required expertise to evaluate a new fused product and prevents the investment into costly capital equipment. When seeking the help of a custom fusion specialist, manufacturers must ensure that all custom formulations for individual customers are solely developed for that particular customer and maintained in strict confidence. The specialist’s objective must be to provide a valuable service to manufacturers by offering the furnaces and expertise to fuse a new product or for the improvement of old products.

About Washington Mills

Washington Mills is a world leader in the manufacture and distribution of abrasive materials and fused mineral products. As the largest producer in North America with sales and manufacturing facilities around the world, our capabilities are unrivaled in the industry. We offer a rich array of abrasive grains and specialty electro-fused minerals. From macro grits to micro grits, to custom specialty fusions, our fused materials are used around the world in hundreds of different industries and applications.

This information has been sourced, reviewed and adapted from materials provided by Washington Mills.

For more information on this source, please visit Washington Mills.


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